Coal furnace having a gas reflector



Aug. 26, 1958 Filed June 2. 1955' G. E. VALENTINE ETAL COAL FURNACE HAVING A GAS REFLECTOR 2 Sheets -Sheet 1 INVENTOR 5 Qatar 6 jle/Vf/ll ATTORNEYS Aug. 26, 1958 G. E. VALENTINE E AL 2,848,982 COAL FURNACE HAVING A GAS REFLECTOR I 2 Sheets-Sheet 2 Filed June 2, 1955 ATTORN United States Patent COAL FURNACE HAVING A GAS REFLECTOR George E. Valentine and Joseph H. Eubanks, Schuylkill Haven, Pa., assignors to V. & E. Products, Inc., Schuylkill Haven, Pa., a corporation of Pennsylvania Application June 2, 1955, Serial No. 512,727

3 Claims. (Cl. 122-368) This invention relates to coal furnaces and more particularly to a draft and combustion gas control arrangement for improving the efliciency of combustion and the transfer of heat from the combustion products. In coal burning furnaces where heat from the combustion products is transferred to water in a boiler, it is desirable to arrange the boiler and heated combustion gas flow such that the maximum amount of heated gas comes in heat transferring relationship with the boiler along as much of the boiler surface as possible.

The present invention includes a novel gas deflection member extending over part of the fire bed which cooperates with both the fire bed and a baflie in the furnace for directing the combustion products toward and along the front surface of the boiler thereby providing an overall path for the combustion products which traverses the entire inside surface of the boiler and adding to the efficiency by approximately 25%.

It is accordingly 2. major object of this invention to provide an improved boiler and furnace arrangement which has increased operating efliciency.

Another object of the present invention is to provide a fire bed having a gas deflector for directing the combustion products along a path adapted to give maximum heat transfer.

Still another object of the present invention is to provide in a furnace with a fire bed and gas deflector, a. baffle having a portion inclined at an angle less than 45 which in cooperation with the top surface of the gas deflector produces a draft stream which directs the flow of combustion products along the front boiler wall.

A still further object of the invention is to provide a furnace having a draft inlet at the ash end of the fire bed and a gas deflector for dividing the draft gas from the inlet into two parts, one passing over the fire bed and the other guided over the gas deflector for directing the combustion gases along the front surface of the boiler wall.

These and other objects of the invention will become more fully apparent as the description proceeds in connection with the drawings wherein:

Figure 1 is a vertical view in section of a furnace incorporating the gas deflector of the present invention; and

Figure 2 is a partial vertical view in section taken along on line 2-2 of Figure 1.

The furnace illustrating the present invention and shown in the drawings includes a moving grate supporting fire bed 12. Coal is supplied to the fire bed through chute 14 from hopper 16 at the front of the furnace. Plate 17 is vertically shiftable through the floor of hopper 16 and adjustable to regulate the thickness of the fire bed. Behind hopper 16 is boiler chamber 18 having a hollow front wall 20 which is inclined upwardly toward the rear of the furnace and extends over a part of fire bed 12. Hollow wall 22 and side walls 24 and 26 (Figure 2) are also part of the boiler and completely surround the fire bed.

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Moving grate 10 is an endless conveyor the upper por-' tion of which passes between guard rails 30. Rotatably mounted wheels 32 and 34 which support the conveyor are intermittently driven in the usual manner as with an electric motor not shown. Draft openings into the furnace are located beneath the fire bed and may be in the form of apertures or louvers 36 in the furnace side wallswhich also may contain access door 38.

Ash chamber 40 is located in the lower part of the furnace and is accessible through ash removal door 42 mounted for pivotal movement about pin 44. The upper section 46 holds drop cleaning door 48 in its closed position.

Water tubes 50 extend from rear wall 22 to front wall 20 over fire bed 12. Baffle 52 is slidably mounted on the water tubes and is movable by handle 54 for removing fiyash from water tubes 50 which accumulates when burning anthracite coal. Fixed baffle 56 extends between side walls 24 and 26 and acts as a barrier between fire bed 12 and flue 58. A motor driven blower (not shown) is located in the flue to supply controlled draft in addition to the natural draft provided by the chimney.

A hollow gas deflecting vessel 60 extends across fire bed 12 and is connected to side walls 24 and 26 thus forming an additional water chamber directly above the fire bed. Lower surface 62 of'the gas deflector extends from the ash end of the fire bed to approximately the point where fire first comes through brightly. This length obviously varies with different size furnaces.

The bottom of gas deflector- 60 is preferably flat and upwardly inclined slightly toward the main flame so that hot gases under surface 62 will be directed toward the main flame and along front boiler wall 20.

Upper surface 64 of the gas deflector inclines from end 66 along a path generally parallel to and at a small distance which by way of illusmltion may be approximately 2 inches from the adjacent section of baffle 56 to form a venturi or passageway of reduced cross-sectional area. The venturi produces a nozzle action for directing the flow of draft gas from the ash end of the fire bed across the top of gas deflector 60 to guide the hot combustion products along the inside of front wall 20. Thus upper surface 64 and the adjacent section of baffle 56 are inclined at a small angle, preferably less than 45 degrees, to be most effective.

When the blower in the flue starts, a siphon action is created in the furnace which removes any gases that may remain under the fire bed due to poor natural draft of the chimney thus causing all gases to be removed through the chimney.

A second venturi or restricted draft passage includes opening 68 of coal chute 14. The blower in the flue also causes a suction down through coal hopper 16 which effects removal of any gases present in this path through the flue.

Since the introduction of draft air is primarily through the furnace walls beneath the fire bed along a path substantially coextensive with the length of the fire bed, the siphon action of the blower causes in addition to the draft flow through the fire bed, a draft gas flow from the ash end of the fire bed toward gas deflector 60. This gas flow splits in two parts along edge of 66 of the gas deflector with one part passing between surface 62 and the fire bed toward the main flame and front wall 20 while the second part goes through the venturi between baffle 56 and upper surface 64 of the gas deflector. This second part of the draft gas flow is accelerated in the direction of the passageway and flows across deflector 60 to direct the flow of the combustion products from the fire bed toward front wall 20 upwardly along the bottom of water chamber 18, across bafiie 52 and down through 3 water tubes 50 to flue inlet 58 adjacent the upper surface of baflle 56.

There has thus been described a furnace having a novel baflie arrangement which provides improved efliciency of combustion of the coal and causes all the gases carrying the heat from the coal burning under the'gas deflector to travel to the front of the boiler thereby obtaining full efiiciency of heat transfer over the entire exposed surface of the boiler 'thus increasing efliciency by approximately 25%.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated 'by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

1. In a furnace, a water compartment, a movable grate under said water compartment, a pair of walls on opposite sides of said grate supporting said compartment, a first hollow end wall connected to said compartment and adapted to contain water, said end wall extending from a position adjacent one end of the grate upwardly and over a central portion of the grate, a second hollow end wall connected to said water compartment, Water tubes connected between said end walls and extending over said grate, a flue outlet adjacent the lower water tubes near said second end wall, a baffle between said flue outlet and said grate, a hollow gas deflecting member between said bafile and said grate, said member having a lower surface slightly inclined to direct hot gases under said lower surface toward said first end wall and an upper surface which with a portion of said baflie forms a passageway of reduced cross-sectional area to direct gas flow across the top of said deflecting member toward said ,first end wall and cause the combustion gases from said-fire bed to pass along said first hollow end wall and under said water compartment, and means connecting said water compartment to the interior of said hollow gas deflecting member.

2. The furnace as defined in claim 1, in combination with a coal hopper having as one side said first hollow end wall, and an opening under said end wall for supplying coal to said grate.

3. In combination, a boiler having depending side and end walls, said end ,walls being, adapted to contain Water, water tubes extending between said end walls, a movable grate under said boiler and between said side walls, a coal chute for supplying coal to one end of said grate, a draft opening beneath said grate, a partition spaced from the end opposite said one end of the grate forming one side of a draft gas passageway, a gas deflection member between said opposite end of said grate and said parti tion for dividing draft gas in said passageway into two parts, one of said parts passing between the gas. deflection member and the grate in a direction toward the end Wall adjacent said coal chute and the other of said parts being deflected over said deflection member and under said partition for direc'ting combustion products toward said boiler end wall, and bafile means adjustably mounted on said water tubes to guide the draft gas in its passage over said water tubes.

References Cited in the file of this patent UNITED STATES PATENTS 617,553 Lutz Jan. 10, 1899 625,916 Alves May 30, 1899 932,440 Brownfield Aug. 31, 1909 1,678,827 Schillinger July 31, 1928 2,316,381 Wright Apr. 13, 1943 FOREIGN PATENTS 480,653 Great Britain Feb. 25, 1938 130,210 Sweden Nov. 28,1950 

